94 Q45t interior fan won't shut off.

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wildmanjim
Posts: 5
Joined: Sun May 02, 2004 10:11 am

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:help,I just found this site,and am very thankful that there is a forum like this . Todays problem is the a/c or heater fan in my 94 Q45t comes on when I turn the key to start the car. it will not turn off. even when I hit the off button on the dash. I had noticed that in the year prior to this occurring ,while cornering sometimes the fan would divert to the defrost or floor for no clear reason( something loose?:confused: ). are these issues related? can anyone tell me where to start looking. I know that the car was hit in the drivers front fender 5 years ago it was nearly a total loss. is that a factor in any of this?

thanks in advance for your help.


911/Q45
Posts: 1376
Joined: Tue Jul 23, 2002 12:10 pm
Car: Autos, Fitness

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There is a fan resistor behind the glove box that can cause the fan to run constantly.

wildmanjim
Posts: 5
Joined: Sun May 02, 2004 10:11 am

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can you tell me what it looks like? I was poking around under the underdash panel a few hours ago and did see a number of wires and connectors near the fan motor. Do you have any idea of the wire colors? BY the way , Thanks for the response,I do appreciate it. :D

Q45tech
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Posts: 14365
Joined: Tue Apr 30, 2002 3:19 am
Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl

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The darligton transistor assembly [what most call a resistor] slips into [mounts] the air box from the front.......all you see is a connector............unscrew and remove and swap.

wildmanjim
Posts: 5
Joined: Sun May 02, 2004 10:11 am

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I am going to call the local dealership and see if I can get one. Thanks for all of your help.

I just looked behind the glovebox (by dropping the underdash panel) there is a blue and white connection that is mounted to the fan box by a phillips screw. It is located just left of center ,under the glovebox. Is this the one you mean?

WILDMAN

Q45tech
Moderator
Posts: 14365
Joined: Tue Apr 30, 2002 3:19 am
Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl

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Take it out and look. It will have many 2-3" long tubular heat sink fins on the rear extending into the air flow.Call our sponsors [with word PARTS in ad] and save 25%.

Consider that it failed for a reason- because the fan motor is getting old and drawing too much current.........so be prepared to change the fan motor soon and replace the variable voltage transistor again if you wait too long.

911/Q45
Posts: 1376
Joined: Tue Jul 23, 2002 12:10 pm
Car: Autos, Fitness

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I think the connection you looked at was the intake sensor, the fan resistor is kind of an odd polygon shape more centered behind the glove box. Call it the fan resistor when you talk to Scottsdale and you'll get the right piece.

natsoundup
Posts: 669
Joined: Fri Jul 26, 2002 4:27 am

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just got one for my 94...about 60 dollars from Scottsdale.... took about 30 minutes to replace...

wildmanjim
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Joined: Sun May 02, 2004 10:11 am

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You guys rock!:ylsuper .........I just had to use that smiley.lol. by the way ,the car had an irregular idle I pulled the MAF , cleaned the connector,tightened the connectors.and then sprayed electrical contact cleaner on the inside of the MAF. This seems to have made a REAL difference in the idle.and yes I bought a a new air filter and began using 93 octane gas, I KNOW ,I thought I could cheese out on the gas and it didn't work. I LOVE this car!!!!

after the fan , I need to fix the left front strut,was leaking now knocking:mad: I intend to fully use the NICO forum and the sponsors to keep this car running right . Once again , THanks for all of the info, BTW, how do you get the glovebox out ? WITHOUT breaking it . I took out the 3 hinge screws and the 2 screws on either side of the opening.it still seemed stuck. I just put the screws back in and left it alone. ...looks like we might have to take a trip to T3 in Atlanta.

natsoundup
Posts: 669
Joined: Fri Jul 26, 2002 4:27 am

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look hard for more screws...

We will have to meet ....since we both live in Greenville...

911/Q45
Posts: 1376
Joined: Tue Jul 23, 2002 12:10 pm
Car: Autos, Fitness

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Two of the screws are behind plugs that you gently pry out.

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wamQ45
Posts: 173
Joined: Thu Jul 25, 2002 10:10 am

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I think that your post is contagious....My 94Q started doing the same thing this morning. Next time please wear protection when posting.

Also, Everything Nissan lists a blower motor relay, is this the part in question.

Q45tech
Moderator
Posts: 14365
Joined: Tue Apr 30, 2002 3:19 am
Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl

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No the blower motor HIGH relay is what bypasses a failed speed controller* and keeps the fan on high.The legal name is " fan control amplifier*" see page HA 135 in 92 FSM.........may be different page in 94-96.

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wamQ45
Posts: 173
Joined: Thu Jul 25, 2002 10:10 am

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I pulled the part in the hopes of fixing or making a new one but the the darlington transistor on the circuit board is not an easy thing to find. It is a NEC 2SD1297 150V 25A 100W Darlington Transistor with Diode. Not sure what the with diode referes to as I can't find the datasheet online. The circuit also consists of a 1 Amp 3.3 volt zener diode, 220 ohm 1/4 watt resistor, 274 pf cap and a 140c thermal cutoff. The circuit it's self is simplistic but the transistor is the issue. There are some sites that have them but the time it would take plus hacking together a new board makes sixty bucks sound real cheap right now.

Q45tech
Moderator
Posts: 14365
Joined: Tue Apr 30, 2002 3:19 am
Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl

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A Darlington transistor is actually 2 or more transisistors.http://en.wikipedia.org/wiki/D...stor.

The circuit assumes a normal draw from the motor for applied voltage. Old age on the motor eventually exceeds the 25 amp capacity of the unit thus it fails.

Just changing the module buys some time but it will fail again from continued exposure to the bad motor. Whether it last 3 years or 30 minutes is a coin flip.

Measure the motor current at various speeds.

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wamQ45
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Joined: Thu Jul 25, 2002 10:10 am

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Well I replace mine today and it go me past the first thirty minutes. If it fails I will replace it with a diy version and also the blower motor. Oh yea... my AC is now functioning correctly. Also, I did get to see the issue with my heater, the levers and such associated with the heater door were broken off, some day!!!

eric95q45
Posts: 40
Joined: Thu Jul 25, 2002 7:58 am

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Does anyone have the part number for the "fan control amplifier"? I've been having the "my a/c fan only runs on high speed" problem.Eric

911/Q45
Posts: 1376
Joined: Tue Jul 23, 2002 12:10 pm
Car: Autos, Fitness

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Just call Scottsdale and they'll get you what you need at the best price.(everthinginfiniti.com)

kutsired
Posts: 4
Joined: Mon Sep 13, 2004 10:45 am
Car: 94 Q45

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This happened to my 94Q a couple of weeks ago. I went and talked with the part guy, and he recommened Part #INF-27761-85E01, it's call "fan control amplifier". Took about half an hour to install. Like magic, the problem is gone.

Q45tech
Moderator
Posts: 14365
Joined: Tue Apr 30, 2002 3:19 am
Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl

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The problem is not gone just band-aided with a transfusion, that old motor will come back to haunt you when you least expect it..............maybe keep a spare amplifier if you don't change the $200 motor.

If you think about it, there are many old electric motors in Q: 4 windows, 4 seats, 1 sunroof, 1wipers, 1 condenser fan, and the HVAC fan which is used more hours than any of the others! 100,000 miles is 5,000-3,000 hours of use.

eric95q45
Posts: 40
Joined: Thu Jul 25, 2002 7:58 am

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Thanks, thats what I was looking for. I order lots of parts from Scottsdale, and Joe is usually very busy, so I end up ordering from someone not quite as familiar with the Q and this board. I was sent a relay that goes in the fuse box in front of the ABS controller.

On another tack, does anyone know if the subharness that connects to the MAF is available and reasonably priced? Or do most people just change the connector? Part numbers?

Thanks for all the help.


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